Taft Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Welder Wildlife Foundation. A median date has an even chance of a later freeze in spring, or an earlier one in fall.
The last spring freeze typically comes around February 24 and the first fall freeze around December 1, a growing season of about 283 days.
- Median at 36°F
- last March 8, first November 18
- Median at 32°F
- last February 24, first December 1
- Median at 28°F
- last January 31, first December 18
Last freeze in spring
The chance of a later freeze than the date shown. At 10 percent, one spring in ten still freezes after the date; planting after the 10 percent date for 32°F is the cautious choice.
| Threshold | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Mar 31 | Mar 21 | Mar 15 | Mar 11 | Mar 8 | Mar 4 | Mar 1 | Feb 24 | Feb 14 |
| 32°F | Mar 15 | Mar 9 | Mar 4 | Mar 1 | Feb 24 | Feb 18 | Feb 10 | Jan 31 | Jan 18 |
| 28°F | Mar 5 | Feb 27 | Feb 19 | Feb 9 | Jan 31 | Jan 24 | Jan 14 | Jan 3 | Dec 24 |
| 24°F | Feb 24 | Feb 7 | Jan 31 | Jan 22 | Jan 12 | Jan 4 | Dec 29 | Dec 23 | Dec 12 |
| 20°F | Feb 12 | Jan 30 | Jan 16 | Jan 7 | Jan 3 | Dec 31 | Dec 27 | Dec 19 | Dec 13 |
| 16°F | – | – | – | – | – | – | – | – | – |
First freeze in fall
The chance of an earlier freeze than the date shown. At 10 percent, one fall in ten freezes before the date.
| Threshold | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Nov 1 | Nov 5 | Nov 10 | Nov 14 | Nov 18 | Nov 23 | Nov 28 | Dec 2 | Dec 9 |
| 32°F | Nov 9 | Nov 16 | Nov 22 | Nov 27 | Dec 1 | Dec 5 | Dec 11 | Dec 20 | Jan 1 |
| 28°F | Nov 22 | Nov 30 | Dec 4 | Dec 10 | Dec 18 | Dec 25 | Jan 1 | Jan 9 | Jan 24 |
| 24°F | Dec 3 | Dec 9 | Dec 16 | Dec 24 | Dec 31 | Jan 4 | Jan 10 | Jan 20 | Feb 3 |
| 20°F | Dec 7 | Dec 14 | Dec 24 | Dec 28 | Jan 1 | Jan 4 | Jan 7 | Jan 18 | Feb 8 |
| 16°F | – | – | – | – | – | – | – | – | – |
Growing season length
Days between the last spring and first fall freeze at each threshold, with the chance of a season at least that long.
| Threshold | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | 287 | 276 | 268 | 262 | 256 | 250 | 244 | 236 | 226 |
| 32°F | 324 | 310 | 301 | 291 | 283 | 276 | 269 | 261 | 252 |
| 28°F | 365 | 353 | 341 | 332 | 323 | 315 | 306 | 295 | 279 |
| 24°F | 365 | 365 | 365 | 365 | 363 | 354 | 342 | 332 | 316 |
| 20°F | 365 | 365 | 365 | 365 | 365 | 365 | 365 | 365 | 353 |
| 16°F | 365 | 365 | 365 | 365 | 365 | 365 | 365 | 365 | 365 |
How often it gets that cold
The share of years with at least one night at or below each temperature.
- 36°F or colder
- 100% of years
- 32°F or colder
- 100% of years
- 28°F or colder
- 90% of years
- 24°F or colder
- 55% of years
- 20°F or colder
- 20% of years
- 16°F or colder
- 2% of years
Degree days
A degree day is one degree of the daily mean temperature beyond a base, for one day. Heating degree days count cold (the fuel a house burns), cooling degree days heat, growing degree days the warmth a crop needs; each crop has its own base.
- Heating degree days, base 65°F
- 1,129
- Cooling degree days, base 65°F
- 3,148
- Growing degree days, base 40°F
- 11,158
- Growing degree days, base 45°F
- 9,366
- Growing degree days, base 50°F
- 7,635
- Growing degree days, base 55°F
- 6,002
- Growing degree days, base 60°F
- 4,496
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 335 | 16 | 200 |
| February | 209 | 33 | 268 |
| March | 110 | 90 | 453 |
| April | 27 | 183 | 606 |
| May | 2 | 364 | 828 |
| June | 0 | 498 | 948 |
| July | 0 | 564 | 1,029 |
| August | 0 | 584 | 1,049 |
| September | 0 | 441 | 891 |
| October | 23 | 257 | 700 |
| November | 134 | 86 | 415 |
| December | 289 | 32 | 248 |
What this means
NOAA computes these from the daily lows at the station over 1991-2020, fitting the dates of each year's last and first freeze to a distribution, so a date can be stated at any level of risk. 36°F is a frost risk for tender plants on a clear, calm night, since the ground cools below the air above it; 32°F is a freeze; 28°F is a hard freeze that kills most annuals.
The station is 15.1 km from Taft. Low ground, valleys and open fields freeze earlier and later than a town center or a hillside.
More
Sources
NOAA NCEI U.S. Climate Normals, 1991-2020, annual and seasonal normals for station USC00419559 (Welder Wildlife Foundation). Public domain.